1. Field of the Invention
The present invention relates to a substrate support plate transfer apparatus for fabricating an organic light emitting display, and more particularly, to a substrate support plate transfer apparatus for fabricating an organic light emitting display configured for the easy replacement of substrate support plates.
2. Description of the Related Technology
Generally, an organic light emitting display is a light emitting display configured to inject electrons from an electron injection electrode and holes from a hole injection electrode into a light emitting layer and to illuminate when excitons, formed when the injected electrons and the injected holes are combined, drop from an excited state to a ground state.
Driving methods of the organic light emitting displays are divided into a passive matrix type and an active matrix type. The passive matrix type of organic light emitting display is simple and its manufacturing method is also simple, but power consumption is high and it is difficult to increase the size of the display device. Larger devices use more wires, and more wires reduce the aperture ratio. Thus, for a small sized display device, a passive matrix type organic light emitting display may be used, and for a large sized display device, the active matrix type organic light emitting display is generally used.
However, in a conventional organic light emitting display, since material for the organic light emitting layer and the cathode electrode has low moisture tolerance and low oxidation resistance, display materials deteriorate over time. The deterioration generates a non-light emitting area called a “dark spot.” The dark spot gradually expands toward the periphery, and eventually the entire display device does not emit light.
Thus, in order to solve the problem, an encapsulation process preventing exposure to moisture and oxygen is carried out. The process comprises pressing a device glass substrate and a sealed glass substrate in which organic light emitting devices are formed with a flat plate and bonding the plates with sealing resin.
Hereinafter, the conventional process of bonding the device glass substrate to the sealed glass substrate is described.
As shown in FIG. 1, a sealed glass substrate 10 is loaded on a substrate support plate 30 and a device glass substrate 1 is suctioned to metal suction plates 20 disposed above the substrate support plate 30. Accordingly, an organic electroluminescent (EL) display device 2 formed on a principal surface of the device glass substrate 1 and a dryer layer 12 formed on a principal surface of the sealed glass substrate 10 are positioned so as to face each other. The suction plate 20 is lowered by a non-depicted moving device, and the suction plate 20 presses the device glass substrate 1 until the distance between the device glass substrate 1 and the sealed glass substrate 10 becomes a predetermined gap G. A UV projection device 40 disposed at the back of the substrate support plate 30 projects UV radiation through the substrate support plate 30 and the sealed glass substrate 10 to the sealing resin 13. In response, the sealing resin 13 hardens so that bonding between the device glass substrate 1 and the sealed glass substrate 10 is completed. As a result, the device glass substrate 1 is bonded to the sealed glass substrate 10, and the organic EL display device 2 formed on the device glass substrate 1 is protected from exposure to, for example, external moisture. This bonding process conventionally occurs within a bonding chamber (not shown), and in order to replace the substrate support plate 30, the bonding chamber is disassembled.
Desirable properties of the substrate support plate 30 are at least that it has sufficient mechanical strength to withstand the pressure applied as the device glass substrate 1 and the sealed glass substrate 10 are pressed toward one another, and that it has sufficient mechanical strength to withstand incidental mechanical impacts which commonly occur when transferring the substrate support plate 30 to or from the bonding chamber. Additionally it is desirable that the substrate support plate 30 have high transmission of the ultraviolet radiation used for hardening the sealing resin 13. As substrate sizes increase, in order to have sufficient mechanical strength the thickness of the substrate support plate 30 also increases. This, of course, reduces the transmission capabilities of the substrate support plate 30 and increases cost. Conventional embodiments of the substrate support plate are made from quartz, but other materials may also be used.